Coded track circuits



May 29, 1945. A. JEROME 2,376,967 7 GODED TRACK CIRCUITS' Filed Sept. 4, 194:5

IN VEN TOR Arflza L.Jepon ze. BY aim H15 ATTORNEY Patented May 29, 1945 copE-n TRACK omcorrs Arthur L. Jerome, EdgeWoodQPa assignor to The 1 Union Switch. &'S ignal Company, Swissvale,v

Pa., a corporationof Pennsylvania..-

' Application September 4, 194's, S e'ri a iJNo. 5111,204

4 Claims. (01. 246-430.),

when; point My invention relates to railway'signaling ap paratus andparticularly to improved means/for indicating at an intermediate point in a track section equipped with coded track circuit apparatus when a train enters the sectiorr.

It' has heretofore been proposed to'provide for a section of railway track a track circuitcomprising a code following track relay at the. en-

trance end of the track section together with means at the exit end of the section for-supplying to the track relay over the section rails impulses of master code which are separated by intervals during which no energy is supplied. l'n additionit has been'proposed to provide means associatedwith the track relay for supplying to the section rails in the intervals, between impulses of master code, impulses of feed-backem' rgy' which operate a feed-back detector at'the exit end of the track section.

Where a track section includes an intersectionwith a highway it is desired to provide meansadjacent the highway governed by' occupancy'off protect the crossing I It is an object ofthis invention to provide the track section for controlling the signals which improved means adapted, for use in a track section equipped with coded track circuit apparatus for indicating at'an intermediate point inthe track'section when a train enters thesection.

' A further object of-the invention is to' provide improved'means'of'the type described which'op- Another ,objectof the invention is toproiv-ide;

means. of the type described which onmovement of a train. through the. track section in either, direction continues operation of the. crossing. sig

nals'. until. the. train 7 clears the, intersection.

out" the novel features thereof-inf l m l U ,1 g

In practicing my invention Iprovide meanslat' the-lexit'end ofa;- track section for supplying to the section mus impulses of'rnaster code to opf erate "the code following track relay at the fen-TE trance end" of the track s'ecti:on; while "the tracli rel'ay li'as associated therewith meansi'forrsupj plying impulses offfeed-jback energy to the see v non rails the intervals between the impulses of" master code, to also cause energytof'kbe'sum plied to the section rails'when the-track'fi elay" is not'fohowingcode. n .An intersection with a highway is located at an intermediate point in the track sectionand'a" first" insulated -jointis located on oneside of the of the" crossing highway i'ntersectionand'a second insulated joint' is located on x the other side of" the intersection anda detector relay is connected'aroundeachof these-joints," while there is means governed'by these detector relays for controlling the crossing si nals for thef intersection. Each of these d-j tector relays is arrang'ed to'be controlled by en ergy 'supplied"from the end ofth'e section on'the v Side Of" the" highway intersection Opposite from mate: the insulated joint around'which the relay": is connected so that'fon movement of'atrain through the section in either direction operation signals will be continued until thetrain'clearsthecrossing; v l

' In a modification offthe inventiononly' one'inj sulated jOintfiS provided'and is located in'ad Other objects of. the. invention and features. of]

novelty will be apparent from the following description taken. inconnection with the accompanyin 'drawing. r i

L shall describe two forms: of coded track-circuit. apparatus embodying myinvention and shalltl tector relaysare connected aroundtliis' jaw ti'o'n ofra'ilway track'equippedwith track cir'cu'it apparatus embodyingmy invention; and

. Fig: 2' is' a diagram showing a'm' whichImay employ. a, l Referring to Fig. 1* of' the drawingthere 'is shown therein a section of railway'trackhavi'ng track rails I and 2' over which trafllc normally moves in the" direction indicated by the arrow;- that'is fror'n left to right; The'railsofthetraick Y sectionf-are' separated" from the rails of the'ad joining-track sections by insulated'joints 3"."

. A code-1 following tracki'relay TR" is -connecte'd across the section rails-r at t the-entrance "end of" the section; while? this rel-ay 'isoperated :by master" code supplied over the section railsfi'omthe'tra'ck battery: at" the; exit end-of the :section: wThe supply of? energy from" thetrack battery 'to r the: section rails": is controlled by a coding relay 2 which maybe-governed in .aymannen well known inthe-art but traflic conditions in the adjacent";

1 section in advance. In a typical system the relay CR may be operated to supply energy of 75 code frequency. to the section-rails when the adjacent section in, advance is occupied andto supply energyof 180 code frequency to thesectlon rails when the adjacent section in advance is vacant. The track relay TR and the detector relay K each have associated therewith a sourceof direct current, not'showm the terminals? of "which are. 1

designated B and Cin the drawing;

. The track section includes an intersection with a, highway, while an insulated joint 5 is located 1 in one of the track rails at a point on the right hand side of the highway-crossing. A detector 'relay K has one terminal. of its winding connected to the track rail atone side ofIthein to'leftQ and track rail 2 to the negative terminal of the battery F33. The energy supplied from battery FB flows through the windings of relays TR andKD- in the wrong direction to pick up I the relay contacts so the contacts of these relays sulated joint 5 while the other terminal of the 1 relay winding is connectedfto the track rail at the other side of the insulated joint. The relay K is of the polar biased type the contacts of which become picked' up when and only when energy flows through the relay winding in aparticular direction, whilez the relay. K controls the supplyof energythrough a decoding transformer to a relay KP. A track railof the;track section .has;an insulated joint'l'l therein at a point on u the lefthand pside of the highway intersection and-a relay KD has its winding connected around the joint 1-. The relay KDcontrols a relay KDP while the relays KP and ,KDP control the cir- I cultsOran-interlocking relay XR which the crossing signalsXS. j coding relay GR is overns When the contact IU of moved-, to itspicked-up position thetrack battaxis-connected across the section ra ls with the f positive terminal .of the battery connected {to track 1 rai1 Accordingly, master-code energy flows 3 frorn the positive terminal. of the battery over-- contact lll of relay CR. trackrall I. winding of track -re1ay -TR-from left to right. back contact l2. of relay IR. track rail {windings of relays remain released at this time. plied from the batteryFB flows through the wind-' ing' of relay K in the right direction to pick up its contacts so the contacts of relay K pick up on-the supply of an impulse of feed-back energy to the section rails. Accordingly, as long as the section -is-yacant the. track relay TR and the 'detector- -relay: KD are operated by master code supplied; over the section rails.- while the relay K-is operated -by feed-back energy supplied over the section rrails.

. Asa result-of code following operation of thetrack relay TR energy is supplied through the de coding-transformer DT- to relaysI-I and IR and the contacts of relay H are maintained picked up, while relay IR operates to supply impulses of feed-back energyto the section rails. The relay- 1 I-I may be, employed in" the well-known manner'to- 1 KDand K'from 1911; right, andtrack rail 2 l to the negat ve terminal ofthe battery 'IB.

Thetrack relay'TR is otthepolarbiasedtype the contact -of which picks up when. and only 1 when. energy flows through the relay windingv in aparticular direction. while the track:relay is connected in the-track circuit -so 'that its contact picks upwhen energy flows through the relaywinding from left to r ght which is the direction 1 in 'whichienergy from thetrack battery flows throu h the windin of the track relay. vi

Similarly; the relayKD is of the polar biased tyne and'is connected with the track rails in such manner'that the relay contact icks'up when energy'fiows through the relay winding from left 1 to right, which isthe direction inwhichenergyv i from the" track battery flows throu hthe winding of this relay.

'The' relay K 'isalso of he polar biased'tytie and'is-con'nected in'the track circuit in such manner' that the 'relay' contacts pick up only when energy flows through the relay winding from ri ht i to left.-'---Accordinglyi when contact In of relay CR picks up to cause energy to be supplied' from I control the signal for the track section and to I control the supply of codedenergy to the rails of theadjacent section in the rear. As a resultof code following operation of relay K energy is supplied through the decoding transformer-:KT to relay -KP to maintain the contacts of relayKP picked up and establish the circuit of -winding20- of relay XR; In addition, on picking'up of; the relay K'a contact 14 of therelay establishes a circuit to supply animpulse of energy from a secondary windingof transformer KT, to a local winding of relayK; The various parts of the apparatus are arranged so'that the energy supplied-from the transformer KT. to relay K is of the same polarity as the energysupplied from 1 the feed-back battery to the track winding of the relay and aids the energy supplied to the track the track'batteryito'the sect onrails energy-flows through the windings of'relays-TRfKDand K.

while'this' ener y will pick 'uo the cont acts ofrelays TR and KD, but

will? not pickup the con tactsof'relay'K.

' Ori movement of the contact of relay QR'to its relasedpos'ition.'thesunply of energy from the' longingthepicked-up periods of the contacts of track'battery to' the section rails is cutoff. while 5 con'ta'cti[0"establishes'connection betwen the section-rails'. -w en the supply ofenergy from the" winding of the'relay to maintain the relay contacts picked up. The energy supplied from the. transformer KT to .the relayK-prolongs thepicked;-up periods of the relayenough to insure that sufficient energy is supplied from transformerKT to relay KP even though the. impulses of feed-back energy are relatively short.

On code following operation of relay KDenergy is supplied through transformer KDT to relay KDPand its contacts arepickecl up toestablish the circuit of winding 23 of relay 2m and as both windings of relay XR' are energizedthe supply of energy to the. crossing signals XS is interrupted and these signalsare n0t,.0perating.' As the relayfKDis operated by master code impulses, and as these impulses are substantially as long as'the ofifintervals between code impulses, it is unnecessary toprovide means for prorelay'KD. r

When the contact Hlof coding relayCR'is picked up it connects thetrack battery TB across the section railsya'n'd when the section is Vacant ---this energy feeds over the section rails" and The energy sup-" code, and these impulses of feed-backcode oper aeration through: theswinding of; reIay'K andllpicks'up re.-- IaySLTR and KD. :Qnmovement; of; the contact ID of codingrelay',tmitsureleasectposi tionthe supply of energy from theitra'ckrbattery' iszcutoff. and; relays; TR and: KD: release. on release of: relay TR and therrelay' IR-ispicked? up momentarilyto supply energy; fromxthe loatteryFB to thesection rails. This energygpicksi' up the contacts of relay-K.

Accordingly, whenthe section-isvacant relays TR and'KD are op'eratedi by the master code im'- pulses,,while; relay K is operated; by the feedback impulses: As track" relay TR follows'code' relay I-I'is pickediup andconnects relay IR1t0 a'secondary winding of 1 the decoding transformer DT, whileasra result of code, followingaoperationof relays: K. andKDthe relays KP and. KDP ares picked up and establish :the: circuits of the wind;- ings of; the interlockingrrelay XR to prevent op'-'- eration of the crossing signals XS.

When a train moving'in-the normal direction ofatearelayt lztorkeeprrelayififipickecliup, rIn-uldi-, tion, the master codetsuppliedtoverrthezsectionl rai1s ;aften the rsection-isvacatedoperatestrelay traflic enters the track sectionthe-trackrelay TR 7 is shunted andnceases'to follow code so relay H releases and'transfers control of'relay IR to a. coding device CT so thatrelay IR continues-to operate to supply impulses of feed-back energy to the section rails. However, because ofrpresence ofthe trainin the tracksection, the energy supplied from the feed-back battery to the section rails is prevented from reaching the relay K 'so' it ceases to follow code and relay KP releases and interrupts the circuit of winding!!! of relay 'XR withxthe result thatcontact 2| releases and-establishes'thecircuit of the-crossing signals XS and they operate to warn users of thehighway of the approach of a train. Atthis time relay KD continues to-be operatedaby master'code supplied to thesection rails so relayKDP is'picked' upand maintains the circuit of the winding 23 of relay'XRl. m

When the train advances beyond joint 1 relay-1 KD is shunted and ceases' tobe. operatedn'l'iy'impulses of master code so relay KDPreleasesand interrupts the circuit of winding 23 ofrelay' XR, but because of the internal construction of the relay the contact is prevented from moving all of the way to its released position;

When. the train advances far enough in the track section for the rear of the train to be located in advance of insulated joint 5; at which time the train will have cleared the intersection, feed-back energy supplied to the section rails as a result of operation of relay IR by the coding device CT will flow through thewinding of relay- K andoperate it so that relay KP is picked. up to establishthe circuit of winding 20 0f relay XR and pick .up contact 2| to discontinue operation of the crossing signals XS. I

The feed-back. energy supplied to thelsection. rails at this timefiows throughthe winding of relay KD, but is ofthe wrong polaritylto operate the relay so its contacts remain released and relay KDP remains released. I t

Whenthe train vacateslthe section master code energy supplied from the trackbattery to the track rails feeds to the track relay during'a reileasedperiod of relay IR and'picks up the track relay so that energy is supplied through the decoding transformer DT to relay H'andit picks'up to transfer control of relay IR from coding device CT to'th'e-decoding transformer D'II Thereafter the relay IR operates in the usual 'manner'to' supply impulses of feed back energy to the section rails in the interval between impulses of" master KB 50. that-relay -KDP picks-up.and:.establishes'- the-circuit of 'thewindingzflpi relay-XRand the equipmentuisnow inv itstnormal condition.

v, The-.apparatusshownhin:Fig; ilalso operatesit provide the' desired; control of the:crossing=tsignals XS onmovement' of a: train through. the

track section in the; reverse of, thenormal direction; v I

When a train; ther tracli-isection" the supplyoflmastercode from theetrack battery over the-:section rails is cutoff Y and relays TR and KD cease to operate so energy isno longer' supplied to. relays: H t and KB? and their contacts-= releasea Onrelease of relay H COIltlOlrO-f relay lRtis transferredfrom the decodup. The. relayKP-is enough: slower in releasing than" the relay-H; to remain picked upat thesetimes until-after relay H releases and causes relay IR, to be operated" byrthe codingd'evice'CT. As relay 'KP remains picked upatv this time it-main- 1 tains'. the 1 circuit of? the winding" 20-= of relay;

and prevents release-of contact-2| rofzrel-ayXR; v Orrrreleaseof relaywK-DP the. circuit of the wind- I ing: 23. of ?r.elay. XR iszinterruptedt and: contact 24:-

releases to initiate operation; of" the crossing signals 255.. v

When the train advancesvbeyondinsulated joint 5 the relay-K is shunted with: respect to energy supplied from battery FBlso' the relay-Kiceases 'to' follow code and relay KP releases: and interrupts the circuit of the winding 20 of relay However, because of thee. internallconstruction of the relay XR' contact '2 I is prevented "from moving to" its released position as: contact 24 is already released. v

When the rearof thetrain advances beyond insulated joint I, at which time the 'train will have cleared the highway intersection, impulses of master code energy-from; the track battery TB feed-to re1ay=KD and operate itsothat energy'ls V supplied through transformer KDT' to relay KDP and the contactof "relay KDP picksupto establish the circuit of winding-'23 of reIay XR; 'Accordingly, contact 24 of relay KR picks'up to 'discon-V tinue operation of thecrossing signals XS, while contact 2| continues to beprevented from moving fercontrol of relay IRfromthecoding device CT to the "decoding'transformenDT. After the trainvacates the track section energysupplied from" the-battery F-B feeds' to the relay-K and operates it so that relay KP picks up and establishesthe circuit" of the- Winding" 20 'offirelay and the equipment is"a;gain"in its: normalicondition.

From theforegoing it will befsee nth'at the apparatus shown inFig; '1" operates to provide the desired control of the crossing signals on""1novement'of'a train through the track 'sec'tioni'n either direction. Furthermore; the apparatusvshown in;

Fig. 1 operates onmovement' ofa trainin either" direction through" the track" section toiconjtinue movingfrom right to left enters clears the highway'intersection,'

operation or the cr'ossing signals until'the'train' Infsome-situation's on rnovement of a train through the trackfsection in' tlie revers'e of the normal direction 'itis not required to maintain operation of the crossing signals until-thetra'in clears Fth'e highway intersection. Where this methodiof control of the crossingsignals is"ade quate the equipment may be arranged 'asshown',

inFig; 2. Referring to this'figure of the drawing the relays K and KD are connected in seriesaround'the J'ointi whichis 'locatedin advance of the highway intersection. The equipment is otherwise. the 'same'as'that shown in Fig. 1 of the; nggl I 1y flAlthough I have'illustratedand described two forms of coded track circuit apparatus embodyin'g myinventiomit is understood that various changes and modifications may bemade therein within the scope of the appended claims without claim is:

departing from the spirit and scope of my inventio'n, M.

. a particular directionfsaiddetector relaysbeing arrangedfso that energy from said first: source" Having thus describedfmy' invention,.what I;

'1. Ina coded railway signaling system, incom; bination; a section of railway track through which trafiic normally moves in agiven' direction, said track 'section having a first and asecond tiacki' rail'and including at an intermediate point inthe" section an intersection with a highway, a crossing signal at said intersection; acoding device at the:

I exit end ofthe section havingv a'contact continu ously actuated between a first position: in which it establishes connection between the sectionrailsi and a second position in which it connects. a first sourceof energy across the section rails with the positive terminal of said source connected to'said first track rail; a code following track relay at the 'entranceend of said track section operatedby.

energy supplied vover thes'ection rails from said first source; means associatefdwith the track;re-' layior connecting across the; track rails in'the'1 intervals during which-the coding device ,contact. is in itsfirst position a second source of. energy with the positive terminalof said source. connected' to saidj'firsttrack rail, a first detector-re,-; lay having its winding connected-in serieswith onetrack rail ofsaid' track section at a-point in; said section on the'side of' the highway'intersec tion adjacent the track relay, a seconddetecton relay having "its winding connected in-serieswitlr one'track rail'of said track section at a'point in} said section on-the side of said highway intersection remote from the track relay, veach of said '3 detector relays'havinga contact which is moved 3 from a first to a second position when and only j tion in which it establishes connection between I the section rails and a se'condposition in which it;connects afirst source of energy across the I section'rails with the positive terminalof said source connected to said first track rail, a code" followingtrack relay at the entrance end of said track section operated by energy supplied over the section railsfrom said first'source, means'as sociated with the track relay for connecting across the track rails in the intervals during which the coding device contact-is in its first posi tion a second source of energy with the positive terminal of said source connectedto said first track raiLafirst and a second detector relay each having a winding connected in series witha track.

rail of said'track section'at a point in said section adjacent saidhighway intersection, each of said detector relays having a contact which is moved from a first to a second position when and only when energy flows through the relay winding in flows'i-throughthe winding of the first detector relay in said particular direction and sothat energy from said second source flows through the wind ing of the second detector relay in said particular direction, andmeans governed by said first and and governing said crosssecond detector relays ingsignal. i

.3. In a coded railway signaling system,:in"conibination, a section of railway track through which traffic normally moves in a given direction;

said tracksection having a firstand a second track rail and. including at an intermediate point in the section an intersection with a highway, 'a

crossing signalat said intersection, a coding tdevice at'the exit end of the section having a con l tactcontinuously actuated between a first position in which it establishes connection between the section rails and a second positioninlwhich it connects a first source of energy across: the

section rails with the positive terminal of said source connected to said first track rail, a code followingtrack'relay at the entrance end of said track section operated by energy supplied-over the section-rails from said first source, mearisi operative when said track relay is responding to when energy flows through the relay winding in 1 aparticular direction, said detector relays being'j arranged sothat energy from saidxfirst source flows" through the winding of the, first detector relay in said particular direction and so that en ergy from said .second source flows through the winding of the second detector relay in said par;

i ticular'ldirection, and means governed by said 1 first and secondcontrolrelays and controlling 1 saidcrossing signal.

2. In a coded railway signaling system, in coma i bination, a sectionof railway track through which trafiic normally moves in a given direction said I track section having a first and a second track rail and including at anintermediate.point in the section an intersectionwith azhighway, a:

which is moved from a firstto'a second position a crossing signal'at said intersection,. a coding de-.

vicegat the ,exit end of the section having a con-1 tactpontiniiously'actuated between a first posi-.

codedenergy to connect across. the track-rails during the released periods of the track relay'a second source of energy with the positive ter- 5 minal-of said source connected to said first track ran, means operative when said track relayi's not responding to coded energy to recurrently connectsaidsecond source oi energy acro'sisthe track rails'with the positive terminal otsaid source connected to said first track rail, a'first detector .relayha'ving its winding connected in series with one track rail of said track'sectionfat a point in'jsaid section on the'side of the highway intersection adjacent the track relay, a second detector'relay having its winding connected; in series with. one track rail of said track section at} a point in said section on the side of said high way; intersection remote from the track relay, each of said detector relays having aficontact when and only when energy flows through the relay winding in a. particular direction, s aid.de-.. tector relays being arranged so; that energy from saidfirst source flows through' the winding of. v the first detector relay in said particular direc-z tion' and so that energy from said second source. flows. throughthe windingof said second de-g' teQtQ!" relay [in said particular direction. andmeans governed by said first and second detector relays and controlling said crossing signal.

4. In a coded railway signaling system, in combination, a section of railway track through which traffic normally moves in a given direction, said track section having a first and a second track rail and including at an intermediate point in the section an intersection with a highway, a crossing signal at said intersection, a coding device at the exit end of the section having a contact continuously actuated between a first position in which it establishes connection between the section rails and a second position in which it connects a first source of energy across the section rails with the positive terminal of said source connected to said first track rail, a code following track relay at the entrance end of said track section operated by energy supplied over the section rails from said first source, means operative when said track relay is responding to coded energy to connect across the track rails during the released eriods of the track relay a second source of energy with the positive terminal of said source connected to said first track rail, means operative when said track relay is not responding to coded energy to recurrently connect said second source of energy across the track rails with the positive terminal of said source connected to said first track rail, a first and a second detector relay each having a winding connected in series with a track rail of said track section at a point in said section adjacent said highway intersection, each of said detector relays having a contact which is moved fromla first to a second position when and only when energy flows through the relay winding in a particular direction, said detector relays being arranged so that energy from said first source flows through the winding of said first detector,

first and second detector relays and controlling said crossing signal.

ARTHUR L; JEROME.

Patent No. 2,376,967.

CERTIFICATE OF CORRECTION.

I y 9 945- ARTHUR L". JEROME- It is hereby certifiedv that error appears in the printeci specification of the above numbered patent requiring correction as follows: Pagegl 11 51;

column, line 65, claim 1, for "control" read "detector"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of September, A. D. 19b5- Leslie Frazer 1 First Assistant Commissioner of Patents. 

